docs: def delay(self,
                gain_in=0.8,
                gain_out=0.5,
                delays=list((1000, 1800)),
                decays=list((0.3, 0.25)),
                parallel=False):
          """delay takes 4 parameters: input gain (max 1), output gain 
          and then two lists, delays and decays.
  
          Each list is a pair of comma seperated values within
          parenthesis.
          """
          self.command.append('echo' + ('s' if parallel else ''))
          self.command.append(gain_in)
          self.command.append(gain_out)
          self.command.extend(list(sum(zip(delays, decays), ())))
          return self